Across the United States, air travel is recovering more quickly from the depths of the pandemic, and it is showing up in longer airport security lines and busier traffic on airline websites. The Transportation Security Administration screened more than 1.3 million people both Friday and Sunday, setting a new high since the coronavirus outbreak devastated travel a year ago. Airlines say they believe the numbers are heading up, with more people booking flights for spring and summer. “Our last three weeks have been the best three weeks since the pandemic hit, and each week has been better than the one prior,” American Airlines CEO Doug Parker said Monday. Airline stocks rose across the board. Shares of the four biggest U.S. carriers hit their highest prices in more than a year. However, the airlines still have far to go before travel fully returns to pre-pandemic levels. While the number of people …